The current study will evaluate the safety, tolerability and analgesic efficacy of ralfinamide in patients with chronic neuropathic low back pain due to nerve compression, i.e., compression radiculopathy or post-traumatic/post-surgical lumbar radiculopathy. It should also be noted that no current drug therapy has global regulatory approval for treating this type of chronic neuropathic low back pain; therefore, should ralfinamide prove effective in this patient population, it would be satisfying an unmet medical need.